This core support grant is intended to provide the baseline level of support required to ensure the maintenance of a research resource, the individual project-associated research is supported by a number of separate project research grants and contracts. All these participating projects share a common goal, namely, improving our understanding of cancer and its genesis and treatment. The several research projects that this core instrument serves share a closely related aim, improvement in understanding the mode of action of radiation and other modalities toward achieving more productive use of these in the treatment and/or induction of cancer. The activities and expenditures covered by this core support grant fall within seven core program categories: professional personnel, administration, animal facilities, instrumentation and facility maintenance, histopathology laboratory service, central glassware service, and media preparation. In addition, modest support is provided by this grant for developmental research, i.e., seed money for new projects.